U.S. patent number 11,344,346 [Application Number 16/454,949] was granted by the patent office on 2022-05-31 for bone plate system.
This patent grant is currently assigned to Pioneer Surgical Technology, Inc.. The grantee listed for this patent is Pioneer Surgical Technology, Inc.. Invention is credited to Matthew P. Gephart.
United States Patent |
11,344,346 |
Gephart |
May 31, 2022 |
Bone plate system
Abstract
In one aspect, a bone plate system that includes a bone plate
having a plurality of elongated through openings. The bone plate
system includes a plurality of bone screws and a plurality of
sliders in the elongated through openings of the bone plate that
receive the bone screws. The bone plate system includes at least
one resilient member for being configured to apply a biasing force
to each of the sliders to urge the slider toward one end portion of
a respective through opening. Further, the bone plate system
includes at least one actuator having an interference position in
which the actuator inhibits shifting of the sliders toward the one
end portion of the through opening and a clearance position in
which the actuator permits the at least one resilient member to
urge the sliders and the bone screws received therein toward the
one end portion of the through openings.
Inventors: |
Gephart; Matthew P. (Marquette,
MI) |
Applicant: |
Name |
City |
State |
Country |
Type |
Pioneer Surgical Technology, Inc. |
Marquette |
MI |
US |
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Assignee: |
Pioneer Surgical Technology,
Inc. (Marquette, MI)
|
Family
ID: |
1000006342837 |
Appl.
No.: |
16/454,949 |
Filed: |
June 27, 2019 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20200000501 A1 |
Jan 2, 2020 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62692464 |
Jun 29, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
17/8047 (20130101); A61B 17/86 (20130101); A61B
2017/00862 (20130101); A61B 2017/564 (20130101) |
Current International
Class: |
A61B
17/80 (20060101); A61B 17/86 (20060101); A61B
17/56 (20060101); A61B 17/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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3808937 |
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Oct 1989 |
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DE |
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0062693 |
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Oct 2000 |
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WO |
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2012162733 |
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Dec 2012 |
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WO |
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Other References
European Communication pursuant to Rules 161(2) and 162 EPC dated
Feb. 9, 2021, in correspondng European Application No. 19824755.3
(3 pages). cited by applicant .
Charlotte Claw Compression Plate, Wright Medical Technology, Inc.,
2 pages, 2015. cited by applicant .
F. Paris, V. Tarazona, E. Blasco, A. Canto, M. Casillas, J. Pastor,
M. Paris, and R. Montero, Surgical stabilization of traumatic flail
chest, Thorax (1975), 30, pp. 521-527. cited by applicant .
Gephart, Matthew P., Bone Plate System, U.S. Appl. No. 62/692,464,
filed Jun. 29, 2018. cited by applicant .
Johnson Matthey Medical Components, How Does Nitinol Work? All
About Nitinol Shape Memory and Superelasticity, retrieved on Jun.
21, 2018;
http://jmmedical.com/resources/122/How-Does-Nitinol-Work%3F-All-About-Nit-
inol-Shape-Memory-and-Superelasticity.html; 2 pages. cited by
applicant .
International Search Report and Written Opinion dated Sep. 17,
2019, in corresponding International Application No.
PCT/US2019/039263 (14 pages). cited by applicant .
Extended European Search Report dated Mar. 17, 2022, in
corresponding European Application No. 19824755.3 (7 pages). cited
by applicant.
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Primary Examiner: Coley; Zade
Attorney, Agent or Firm: Fitch, Even, Tabin & Flannery
LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application claims benefit of U.S. Provisional Application No.
62/692,464, filed Jun. 29, 2018, which is hereby incorporated
herein by reference in its entirety.
Claims
What is claimed is:
1. A bone plate system comprising: a bone plate; a plurality of
elongated through openings of the bone plate, each elongated
through opening having a pair of end portions across the through
opening from each other; a plurality of bone screws each having a
head portion and a shank portion, the shank portion configured to
be driven into bone; a plurality of sliders in the elongated
through openings and having throughbores configured to receive the
head portions of the bone screws, the sliders and the bone screw
head portions received therein being shiftable within the elongated
through openings relative to the bone plate; at least one resilient
member having a loaded configuration wherein the at least one
resilient member is configured to apply a biasing force to the
sliders and urge each of the sliders toward one end portion of a
respective through opening; at least one actuator having an
interference position in which the actuator maintains the at least
one resilient member in the loaded configuration and inhibits
shifting of the sliders toward the one end portion of the
respective through openings and a clearance position in which the
actuator permits the at least one resilient member to urge the
sliders and the bone screws received therein along the through
openings of the rigid bone plate and toward the one end portion of
the through openings; and wherein the at least one resilient member
in the loaded configuration thereof contacts the bone plate and the
sliders and applies the biasing force to the sliders to urge the
sliders toward the one end portion of the through openings.
2. The bone plate system of claim 1 wherein the at least one
actuator in the interference position thereof keeps each of the
sliders at an opposite end portion of the respective through
opening.
3. The bone plate system of claim 1 wherein the at least one
resilient member includes a plurality of elongated resilient wires
each associated with one of the sliders.
4. The bone plate system of claim 1 wherein the at least one
resilient member includes a pair of resilient members secured to
each of the sliders, each resilient member having a pair of
portions connecting the slider to the bone plate.
5. The bone plate system of claim 1 wherein the at least one
actuator includes a plurality of actuators each having a head
portion configured to be engaged by an actuator removal instrument
and a body portion held between one of the sliders and the bone
plate with the actuator in the interference position.
6. The bone plate system of claim 1 wherein the bone plate includes
a flat wall portion extending along one of the through openings and
one of the sliders includes a flat wall portion facing the flat
wall portion of the bone plate; and the at least one actuator has a
pair of flats engaged with the flat wall portions of the bone plate
and the one slider with the actuator in the interference
position.
7. The bone plate system of claim 1 wherein at least one of the
sliders includes a pair of through bores sized to receive head
portions of a pair of bone screws.
8. The bone plate system of claim 1 wherein the bone plate has a
unitary, one-piece construction.
9. The bone plate system of claim 1 wherein the sliders are rigid
and do not deform with seating of the bone anchor head portions in
the throughbores of the sliders.
10. The bone plate system of claim 1 wherein the at least one
resilient member is in the loaded configuration with the at least
one actuator in the interference position and applies a biasing
force against each of the sliders to clamp the at least one
actuator between the sliders and the bone plate, and the at least
one resilient member shifts toward an unloaded configuration with
the at least one actuator in the clearance position.
11. The bone plate system of claim 1 wherein there is a single
slider in each of the elongated through openings of the bone
plate.
12. The bone plate system of claim 1 wherein the bone plate and the
slider have openings and surfaces defining the openings; wherein
the at least one resilient member extends in the openings; and
wherein the at least one resilient member engages the surfaces
defining the openings of the bone plate and slider with the
actuator in the interference position.
13. A bone plate system comprising: a bone plate; a plurality of
elongated through openings of the bone plate, each elongated
through opening having a pair of end portions across the through
opening from each other; a plurality of bone screws each having a
head portion and a shank portion, the shank portion configured to
be driven into bone; a plurality of sliders in the elongated
through openings and having throughbores configured to receive the
head portions of the bone screws, the sliders and the bone screw
head portions received therein being shiftable within the elongated
through openings relative to the bone plate; at least one resilient
member for being configured to apply a biasing force to the sliders
to urge each of the sliders toward one end portion of a respective
through opening; at least one actuator having an interference
position in which the actuator inhibits shifting of the sliders
toward the one end portion of the respective through openings and a
clearance position in which the actuator permits the at least one
resilient member to urge the sliders and the bone screws received
therein along the through openings of the rigid bone plate and
toward the one end portion of the through openings; and wherein the
at least one resilient member includes a plurality of elongated
resilient members each having a pair of opposite end portions and
an intermediate portion between the end portions, the intermediate
portion supported by one of the sliders and the end portions
supported by the bone plate.
14. A bone plate system comprising: a bone plate; a plurality of
elongated through openings of the bone plate, each elongated
through opening having a pair of end portions across the through
opening from each other; a plurality of bone screws each having a
head portion and a shank portion, the shank portion configured to
be driven into bone; a plurality of sliders in the elongated
through openings and having throughbores configured to receive the
head portions of the bone screws, the sliders and the bone screw
head portions received therein being shiftable within the elongated
through openings relative to the bone plate; at least one resilient
member for being configured to apply a biasing force to the sliders
to urge each of the sliders toward one end portion of a respective
through opening; at least one actuator having an interference
position in which the actuator inhibits shifting of the sliders
toward the one end portion of the respective through openings and a
clearance position in which the actuator permits the at least one
resilient member to urge the sliders and the bone screws received
therein along the through openings of the rigid bone plate and
toward the one end portion of the through openings; and wherein the
at least one resilient member includes a plurality of resilient
members each extending between one of the sliders and the bone
plate, each resilient member having a deformed configuration
including a bent portion with the at least one actuator in the
interference position, the bent portion being allowed to straighten
toward a non-deformed configuration thereof with the at least one
actuator in the clearance position.
15. A bone plate system for securing a pair of bones, the bone
plate system comprising: a bone plate; a pair of elongated through
openings of the bone plate; a pair of bone screws for securing the
bone plate to the pair of bones, each bone screw having a head
portion and a shank portion; a pair of sliders in the elongated
through openings of the bone plate, each slider having a through
bore configured to permit the shank portion of one of the bone
screws to be driven through the through bore and into a bone and
the head portion to be seated in the through bore; at least one
actuator configured to be clamped between the sliders and the bone
plate; at least one resilient member extending in the through
openings of the bone plate between the bone plate and the sliders,
the at least one resilient member configured for applying a biasing
force to the sliders to urge the sliders against the at least one
actuator and cause the sliders to clamp the at least one actuator
between the sliders and the bone plate; and the at least one
actuator being removable from being clamped between the sliders and
the bone plate so that the biasing force applied by the at least
one resilient member extending in the through openings of the bone
plate urges each slider and the bone screw therein toward the other
slider and bone screw for compressing the bones together.
16. The bone plate system of claim 15 wherein the at least one
resilient member includes at least one elongated resilient
wire.
17. The bone plate system of claim 15 wherein the at least one
resilient member includes at least one resilient member associated
with each of the sliders.
18. The bone plate system of claim 17 wherein the at least one
resilient member connects the associated slider to the bone plate
and supports the slider in the through opening of the bone
plate.
19. The bone plate system of claim 17 wherein each slider includes
a pair of support surfaces extending transversely to one another
and the at least one resilient member associated with the slider
has a loaded configuration wherein portions of the resilient member
extend along the support surfaces and an unloaded configuration
wherein the portions of the resilient member are spaced from the
support surfaces.
20. The bone plate system of claim 15 wherein each slider includes
opposite sides and at least one passageway extending intermediate
the sides sized to permit the at least one resilient member to
extend therethrough.
21. The bone plate system of claim 15 wherein the at least one
actuator includes a plurality of actuators each having a head
portion configured to be engaged by an actuator removal instrument
and a body portion for being clamped between one of the sliders and
the bone plate and resisting shifting of the slider toward the
other slider.
22. The bone plate system of claim 15 wherein the at least one
resilient member includes superelastic nitinol.
23. The bone plate system of claim 15 wherein the at least one
resilient member including an elongate resilient member having a
first portion secured to the bone plate, a second portion secured
to one of the sliders, and an intermediate portion between the
first and second portions along the elongate resilient member
extending from the bone plate to the one slider.
24. The bone plate system of claim 15 wherein the bone plate
includes a first opening and the slider includes a second opening;
and wherein the at least one resilient member extends in the first
and second openings.
25. A bone plate system for securing a pair of bones, the bone
plate system comprising: a bone plate; a pair of elongated through
openings of the bone plate; a pair of bone screws for securing the
bone plate to the pair of bones, each bone screw having a head
portion and a shank portion; a pair of sliders in the elongated
through openings of the bone plate, each slider having a through
bore configured to permit the shank portion of one of the bone
screws to be driven through the through bore and into a bone and
the head portion to be seated in the through bore; at least one
actuator configured to be clamped between the sliders and the bone
plate; at least one resilient member configured for applying a
biasing force to the sliders to urge the sliders against the at
least one actuator and cause the sliders to clamp the at least one
actuator between the sliders and the bone plate; and the at least
one actuator being removable from being clamped between the sliders
and the bone plate so that the biasing force urges each slider and
the bone screw therein toward the other slider and bone screw for
compressing the bones together; and wherein the at least one
resilient member includes at least one elongated resilient wire;
wherein the at least one elongated resilient wire includes a pair
of elongated resilient wires secured to each of the sliders that
connect the sliders to the bone plate.
26. A bone plate system for securing a pair of bones, the bone
plate system comprising: a bone plate; a pair of elongated through
openings of the bone plate; a pair of bone screws for securing the
bone plate to the pair of bones, each bone screw having a head
portion and a shank portion; a pair of sliders in the elongated
through openings of the bone plate, each slider having a through
bore configured to permit the shank portion of one of the bone
screws to be driven through the through bore and into a bone and
the head portion to be seated in the through bore; at least one
actuator configured to be clamped between the sliders and the bone
plate; at least one resilient member configured for applying a
biasing force to the sliders to urge the sliders against the at
least one actuator and cause the sliders to clamp the at least one
actuator between the sliders and the bone plate; the at least one
actuator being removable from being clamped between the sliders and
the bone plate so that the biasing force urges each slider and the
bone screw therein toward the other slider and bone screw for
compressing the bones together; and wherein the at least one
resilient member includes at least one bend with the actuator
clamped between the sliders and the bone plate and the at least one
bend straightens in response to the at least one actuator being
removed from being clamped between the sliders and the bone
plate.
27. A bone plate system for securing a pair of bones, the bone
plate system comprising: a bone plate; a pair of elongated through
openings of the bone plate; a pair of bone screws for securing the
bone plate to the pair of bones, each bone screw having a head
portion and a shank portion; a pair of sliders in the elongated
through openings of the bone plate, each slider having a through
bore configured to permit the shank portion of one of the bone
screws to be driven through the through bore and into a bone and
the head portion to be seated in the through bore; at least one
actuator configured to be clamped between the sliders and the bone
plate; at least one resilient member configured for applying a
biasing force to the sliders to urge the sliders against the at
least one actuator and cause the sliders to clamp the at least one
actuator between the sliders and the bone plate; and the at least
one actuator being removable from being clamped between the sliders
and the bone plate so that the biasing force urges each slider and
the bone screw therein toward the other slider and bone screw for
compressing the bones together; wherein each slider includes
opposite sides and at least one passageway extending intermediate
the sides sized to permit the at least one resilient member to
extend therethrough; and wherein the at least one resilient member
has a pair of portions that pivot within the passageway in response
to the at least one actuator being removed from being clamped
between the sliders and the bone plate and the at least one
passageway includes an enlarged portion at each of the sides that
permits the pivotal movement of the portions of the resilient
member.
28. A bone plate system for securing a pair of bones, the bone
plate system comprising: a bone plate; a pair of elongated through
openings of the bone plate; a pair of bone screws for securing the
bone plate to the pair of bones, each bone screw having a head
portion and a shank portion; a pair of sliders in the elongated
through openings of the bone plate, each slider having a through
bore configured to permit the shank portion of one of the bone
screws to be driven through the through bore and into a bone and
the head portion to be seated in the through bore; at least one
actuator configured to be clamped between the sliders and the bone
plate; at least one resilient member configured for applying a
biasing force to the sliders to urge the sliders against the at
least one actuator and cause the sliders to clamp the at least one
actuator between the sliders and the bone plate; the at least one
actuator being removable from being clamped between the sliders and
the bone plate so that the biasing force urges each slider and the
bone screw therein toward the other slider and bone screw for
compressing the bones together; wherein each slider includes
opposite sides and at least one passageway extending intermediate
the sides sized to permit the at least one resilient member to
extend therethrough; and wherein the at least one passageway
includes a pair of passageways extending intermediate the sides and
the at least one resilient member includes a pair of resilient
wires associated with each of the sliders that extend through the
passageways.
Description
FIELD
The present disclosure relates to bone plate systems that are
secured to bones and, more specifically, to bone plate systems for
being secured to bones and compressing the bones together to
facilitate fusion of the bones.
BACKGROUND
Bone plate systems are known for stabilizing bones. As used herein,
the term "bone" refers to a whole bone or a portion of a bone. The
bones stabilized by a bone plate system may be, for example,
portions of a single bone such as a broken clavicle bone or
separate vertebrae. One application of bone plate systems is to
secure two or more vertebrae together with an intervertebral
implant between the vertebrae. Another application of bone plate
systems is to fuse portions of a bone that have been separated by a
break or a cut. For example, a bone plate system may be used to
facilitate fusion of portions of a broken bone of a clavicle,
scapula, foot, or other extremity.
SUMMARY
In accordance with one aspect of the present disclosure, a bone
plate system is provided that includes a bone plate having a
plurality of elongated through openings. Each elongated through
opening has a pair of end portions across the through opening from
each other. The bone plate system includes a plurality of bone
screws each having a head portion and a shank portion, the shank
portion being configured to be driven into a bone. The bone plate
system includes a plurality of sliders in the elongated through
openings of the bone plate. Each slider has a throughbore
configured to receive the head portion of one of the bone anchors.
The sliders and bone screw head portions received therein are
shiftable within the elongated through openings relative to the
bone plate. The bone plate system includes at least one resilient
member for being configured to apply a biasing force to each of the
sliders to urge the slider toward one end portion of a respective
through opening. Further, the bone plate system includes at least
one actuator having an interference position in which the actuator
inhibits shifting of the sliders toward the one end portion of the
respective through opening. The at least one actuator also has a
clearance position in which the actuator permits the at least one
resilient member to urge the sliders and the bone screws received
therein toward the one end portion of the through openings. In this
manner, the bone plate system may be secured to bones and the at
least one actuator moved from the interference position to the
clearance position to cause the at least one resilient member to
urge the sliders and bone screws along the elongated through
openings and compress the bones together. Further, the bone plate
is made of a rigid material such as titanium to resist
post-surgical loading from the bones and keep the bones compressed
together.
The present disclosure also provides a bone plate system for
securing a pair of bones. The bone plate system includes a bone
plate, elongated through openings of the bone plate, and a pair of
bone screws for securing the bone plate to the bones. The bone
plate system further includes a pair of sliders in the elongated
through openings that each have a through bore for receiving a bone
screw and at least one actuator configured to be clamped between
the sliders and the bone plate. Further, the bone plate system
includes at least one resilient member configured for applying a
biasing force to the sliders to urge the sliders against the at
least one actuator and cause the sliders to clamp the at least one
actuator between the sliders and the bone plate. The at least one
actuator is removable from being clamped between the sliders and
the bone plate so that the biasing force urges each slider and the
bone screw therein toward the other slider and bone screw for
compressing the bones together. The bone plate system thereby
provides a secure assembly of the at least one actuator clamped
between the sliders and the bone plate which improves the ease of
handling of the bone plate system during installation. Further, the
at least one resilient member provides an easy-to-use approach for
applying a biasing force against the bones by removing the at least
one actuator from the bone plate.
In accordance with another aspect of the present disclosure, a
method is provided for compressing a pair of bones. The method
includes positioning a bone plate against bones and driving shanks
of bone screws into through bores of sliders in elongated through
openings of the bone plate and into engagement with the bones. The
method includes removing at least one actuator from the bone plate
and permitting at least one resilient member to urge the sliders
and bone screw head portions therein toward each other along the
elongated through openings of the bone plate and compress the bones
together. In this manner, the method can be utilized to quickly
secure the bone plate to the bones by driving the bone screws into
through bores of the sliders and compress the bones by removing the
at least one actuator from the bone plate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a bone plate system including a
bone plate, slider assemblies in elongated through openings of the
bone plate, bone screws in the slider assemblies, and removable
spacers that keep the slider assemblies at one end of the through
openings;
FIG. 2 is a cross-sectional view taken across line 2-2 of in FIG. 1
showing bodies of the spacers spacing sliders of the slider
assemblies from walls of the bone plate;
FIG. 3 is a top plan view of the bone plate system of FIG. 1
secured to bones having a gap therebetween;
FIG. 4 is a cross-sectional view taken across line 4-4 in FIG. 2
showing resilient wires of the slider assemblies in a loaded
configuration which clamps the spacers between the sliders and the
bone plate;
FIG. 5 is a view similar to FIG. 3 showing the spacers removed and
the resilient wires having urged the sliders and bone screws
received therein toward opposite ends of the elongated through
openings which compresses the bones;
FIG. 6 is a cross-sectional view similar to FIG. 4 showing the
resilient wires in an unloaded configuration after the spacers have
been removed and the resilient wires have shifted the sliders
toward the ends of the elongated through openings;
FIG. 7 is a stress-strain diagram of properties of super-elastic
nitinol;
FIG. 8 is an exploded view of the bone plate system of FIG. 1
showing the bone plate, sliders, and resilient wires;
FIG. 9A is a cross-sectional view of the bone plate taken at one of
the through openings of the bone plate;
FIG. 9B is a cross-sectional view taken across line 9B-9B in FIG.
9A showing a slider in the through openings of the bone plate and a
bone anchor received in a through bore of the slider;
FIG. 10 is cross-sectional view taken across line 10-10 in FIG. 9A
showing through apertures of a side wall of the bone plate that
receive ends of the resilient wires;
FIG. 11 is a perspective view of one of the sliders of FIG. 8
showing passageways of the slider that receive resilient wires;
FIG. 12 is a side elevational view of the slider of FIG. 11 showing
the passageways extending through the slider;
FIG. 13 is an end elevational view of the slider of FIG. 11 showing
enlarged portions of one of the passageways of the slider that
accommodate movement of portions of the resilient wire that extends
through the passageway;
FIG. 14 is a cross-sectional view of the slider taken across line
14-14 in FIG. 13 showing the passageways of the slider having
angled surfaces and curved surfaces to support the resilient wires
in the loaded configuration thereof;
FIG. 15 is a cross-sectional view similar to FIG. 14 showing the
resilient wires extending in the passageways of the slider and in
the loaded configuration thereof with portions of the resilient
wires extending along the angled surfaces and curved surfaces of
the slider passageways;
FIG. 16 is a cross-sectional view similar to FIG. 15 showing the
resilient wires in an unloaded configuration wherein the portions
of the resilient wires have pivoted to a straight configuration
wherein the portions are spaced from the inclined surfaces and
curved surfaces of the passageways;
FIG. 17 is a side elevational view of one of the spacers of the
bone plate system of FIG. 1 showing notches of the spacer that
receive a slider on one side of the spacer and a wall of the bone
plate on the other side of the spacer;
FIG. 18 is a cross-sectional view of one of the bone screws of the
bone plate system of FIG. 1;
FIG. 19 is a perspective view of an instrument for removing the
spacers of the bone plate system of FIG. 1;
FIG. 20 is a cross-sectional view taken across line 20-20 in FIG.
19 showing an inner shaft of the instrument that is shiftable
relative to an outer shaft of the instrument;
FIG. 21A is a cross-sectional view taken generally along line
21A-21A in FIG. 20 showing resilient fingers of the inner shaft
engaging an underside of a head of a spacer of a bone plate
system;
FIG. 21B is a cross-sectional view of the instrument and bone plate
system of FIG. 21A taken generally perpendicular to the
cross-section of FIG. 21A and showing the inner shaft engaged with
the head of the spacer and the outer sleeve abutting an upper
surface of the bone plate;
FIG. 21C is a cross-sectional view similar to FIG. 21B showing the
inner shaft shifted proximally relative to the outer sleeve which
removes the spacer from a gap between a slider and a wall of the
bone plate;
FIG. 21D is a cross-sectional view similar to FIG. 21B showing the
inner shaft engaged with the head of a second spacer while the
inner shaft contains a first spacer from a previous spacer-removing
procedure;
FIG. 21E is a cross-sectional view similar to FIG. 21D showing the
inner shaft shifted proximally relative to the outer sleeve which
removes the second spacer from a gap between a slider and a wall of
the bone plate;
FIG. 22 is a perspective view of another bone plate system, the
bone plate system having a slider assembly that receives two bones
screws;
FIG. 23 is a top plan view of the two bone screw-receiving slider
assembly of FIG. 22 including a slider and resilient wires having
end portions that extend outward from sides of the slider;
FIG. 24 is side elevational view of the slider assembly of FIG. 23
showing the end portions of the wires extending outward from
passages of the slider;
FIG. 25 is a front elevational view of the slider of FIG. 23
showing a curvature of the slider;
FIG. 26 is a cross-sectional view taken generally across line 26-26
in FIG. 24 showing the wires in loaded configuration and extending
along an angled support surface and a curved support surface of the
slider;
FIG. 27 is a cross-sectional view taken across line 27-27 in FIG.
23 showing an angle between portions of one of the passageways of
the slider;
FIG. 28 is a top plan view of the resilient wire which extends
through the passageway of FIG. 27 showing the wire in a loaded
configuration;
FIG. 29 is a front elevational view of the wire of FIG. 28 showing
the wire in the loaded configuration;
FIG. 30 is a side elevational view of the wire of FIG. 28 in the
loaded configuration;
FIG. 31 is a perspective view of a bone plate system having a dog
bone-shaped bone plate;
FIG. 32 is a perspective view of another bone plate having through
openings for receiving sliders and openings in side walls of the
bone plate for receiving resilient wires that urge the sliders in
predetermined directions within the throughbores;
FIG. 33 is an end elevational view of the bone plate of FIG. 32
showing a reduced thickness of the bone plate in a middle of the
bone plate;
FIG. 34 is a cross-sectional view of a portion of the bone plate of
FIG. 32 taken across line 34-34 in FIG. 32 showing apertures in one
of the side walls of the bone plate for receiving the resilient
wires of a slider received in the associated through opening;
and
FIG. 35 is a cross-sectional view of a portion of the bone plate of
FIG. 32 taken across line 35-35 in FIG. 32 showing the geometry of
the apertures of the side walls of the bone plate.
DETAILED DESCRIPTION
With reference to FIG. 1, a bone plate system 10 is provided that
includes a bone plate 12 having one or more through openings 14
therein that receive one or more slider assemblies 16. The slider
assemblies 16 each include a slider 18 and one or more resilient
members such as wires 20, 22 (see FIG. 4). The wires 20, 22 have a
loaded configuration wherein the wires 20, 22 apply a biasing force
to the sliders 18 which urges each of the sliders 18 toward one end
portion 64 (see FIG. 2) of the respective through opening 14. The
bone plate system 10 also includes at least one actuator, such as
spacers 36, which resist movement of the sliders 18 toward the one
end portion 64 of the respective through opening 14 and keep the
wires 20, 22 in a loaded configuration. Because the spacers 36 keep
the wires 20, 22 in the loaded configuration, the wires 20, 22 have
a preload that may be released by removing the spacers 36 from the
through openings 14. The sliders 18 include sliders 18A, 18B for
being secured to a first bone 86 (see FIG. 3) and sliders 18C, 18D
for being secured to a second bone 84. The sliders 18 each include
one or more through bores 32 that receive bone anchors such as bone
screws 30.
To install the bone plate system 10, the bone plate 12 is
positioned against the bones 84, 86 and the bone screws 30 are
driven into the through bores 32 of the sliders 18 and into the
bones 84, 86 until head portions 34 of the bone screws 30 are
seated in the through bores 32 of the sliders 18 as shown in FIG.
1. Next, a user operates the at least one actuator to cause the
bone plate system 10 to compress the bones 84, 86. In one
embodiment, the user operates the at least one actuator by removing
the spacers 36 from the bone plate 12 generally in direction 38.
Once the spacers 36 have been removed, the wires 20, 22 of the
slider assemblies 16 can unload and urge the sliders 18A, 18B and
bone screws 30 therein in direction 24 and urge the sliders 18C,
18D and bone screws 30 therein in direction 26. This compresses the
bones 84, 86 together as shown in FIG. 5. Compressing the bones 84,
86 encourages fusion of the bones 84, 86 together or, in another
embodiment, fusion of the bones 84, 86 together with a device
therebetween such as an intervertebral implant between two
vertebrae.
With reference to FIG. 2, the spacers 36 each include a head 40 and
a body 42. The head 40 is configured to be engaged by an actuator
removal instrument such as spacer removal instrument 50 (see FIG.
19). With reference to the slider 18D, the body 42 of the spacer 36
is sized to extend into one of the through openings 14 and separate
the slider 18D from a laterally extending wall 52 of the bone plate
12. More specifically, the body 42 includes flats 54, 56 with the
flat 54 engaging a flat surface 58 of the slider 18D and the flat
56 engaging a flat surface 60 of the wall 52. With the spacer 36
connected to the bone plate 12, the presence of the spacer body 42
in the through opening 14 keeps the slider 18D at one end portion
62 of the through bore 32 and maintains the wires 20, 22 in a
loaded configuration (see FIG. 4). The biasing force provided by
the wires 20, 22 clamps the body 42 of the spacer 36 between the
slider 18D and the wall 52 of the bone plate 12. By removing the
spacers 36 from the bone plate 12, the wires 20, 22 can shift
slider 18D in direction 24 toward an opposite end portion 64 of the
through opening 14. The sliders 18A, 18B, 18C operate in a similar
manner as discussed with respect to slider 18D.
The bone plate 12, sliders 18, and spacers 36 are made of rigid
materials meaning that they are not intended to deform during
normal installation and post-surgical use of the bone plate system
10. In one example, the bone plate 12, sliders 18, and spacers 36
are made of a metallic material such as titanium. The rigidity of
the spacers 36 keeps the wires 20, 22 from being able to shift to
the unloaded configuration thereof while the spacers 36 are present
in the through openings 14.
The wires 20, 22 are made of a resilient material meaning that the
wires 20, 22 are deformable and are able to recoil or spring back
to shape after bending. Other resilient members may be used such as
resilient members that recoil or spring back to shape after being
stretched or compressed. The wires 20, 22 together apply a
predetermined biasing force to the respective slider 18 such as in
the range of approximately five pounds to approximately fifteen
pounds, such as approximately ten pounds of force. The wires 20, 22
of the sliders 18 are also additive with the other levels of the
bone plate 12 so that, with four sliders 18, the sliders 18 and
bone screws 30 therein compress the bones 84, 86 with a compressive
force of forty pounds.
In one example, the wires 20, 22 are made of a superelastic
material. The superelastic material may be a metallic material such
as superelastic nitinol. As an example, the wires 20, 22 may be
made of superelastic nitinol and may each have a diameter of 0.028
inches. The bone plate system 10 utilizing these wires 20, 22 may
provide 63 lbs of compressive force. The biasing force of the wires
20, 22 increases rapidly with relatively small increases in
diameter. For example, the bone plate system 10 utilizing
superelastic nitinol wires 20, 22 each having a diameter of 0.035
inches may provide 141 lbs of compressive force.
As used herein, the terms loaded configuration and unloaded
configuration with reference to wires 20, 22 are relative terms
wherein the wires 20, 22 are loaded or deformed more in the loaded
configuration than in the unloaded configuration. Thus, when the
wires 20, 22 are described as being in the unloaded configuration,
it is not intended that the wires 20, 22 must be completely
unloaded, just that the wires 20, 22 are less loaded or deformed
than when the wires are in the loaded configuration.
Regarding FIG. 2, the spacer 36 is configured to facilitate removal
of the spacer 36 by the spacer removal instrument 50. In one form,
the spacer 36 includes a shoulder 70 that seats on an upper surface
72 of the bone plate 12. The shoulder 70 positions an underside
surface 74 of the head 40 at distance 76 above the bone plate upper
surface 72. The distance 76 creates a gap 78 of the bone plate
12/spacer 36 assembly into which a portion of the instrument 50 may
fit and engage the underside surface 74 of the head 40. The bone
plate 12 has a lower surface 80 opposite the upper surface 72 for
being positioned against the bones 84, 86. The lower surface 80 may
have a concave curvature to compliment the external surfaces of the
bones 84, 86.
With reference to FIG. 3, the bone plate 12 has been positioned
against the bones 84, 86 which are separated by a small gap 88. The
bone screws 30 have been driven into the through bores 32 of the
sliders 18. In the embodiment of FIG. 3, the bone plate 12 has a
longitudinal axis 90 and all of the sliders 18A, 18B, 18C, 18D are
aligned along the longitudinal axis. This provides a small
footprint for the bone plate 12 on the bones 84, 86 and is well
suited for narrow bones such as bones of the clavicle, foot, or
other extremities.
With reference to FIG. 4, the spacers 36 are connected to bone
plate 12 and hold the sliders 18 at the end portion 62 of the
through openings 14. Because the sliders 18 are held at the end
portion 62 of the through openings 14, the sliders 18 maintain the
wires 20, 22 in the loaded configuration. The wires 20, 22 extend
through passageways 23, 25 (see FIG. 8) of the sliders 18 and have
a bent configuration around walls 100, 102 of the sliders 18. The
wires 20, 22 each have an intermediate portion 107 secured to the
slider 18. In one embodiment, the intermediate portion 107 is
secured to the slider 18 such as by forming a dimple in an upper
surface 109 (see FIG. 11) of an upper wall 111 of the slider 18
which deforms the upper wall 111 into engagement with the
intermediate portion 107.
Regarding FIG. 4, the wires 20, 22 include end portions 104, 106
extending out of the passageways 23, 25 and are received in
wire-receiving portions 110, 112 of the bone plate 12. The
wire-receiving portions 110, 112 include pairs of apertures 114,
116 that receive wire end portions 104, 106. More specifically, the
end portions 104, 106 of the wire 20 extend out of the passageway
23 and into apertures 114, 116 of the bone plate 12. Likewise, the
end portions 104, 106 of the wire 22 extend out of the passageway
25 and into apertures 114, 116 of the bone plate 12. The wires 20,
22 support the sliders 18 in the through openings 14. The wires 20,
22 are made of a material and have a diameter sufficient to provide
pull-through resistance for the sliders 18 such that the sliders 18
and bone screws 30 therein stay within the through openings 14 of
the bone plate 12 despite loads applied to the bone screws 30 by
the bones 84, 86.
With reference to FIG. 5, the spacers 36 have been removed from the
bone plate 12 which permits the wires 20, 22 to unload by
straightening. The unloading wires 20, 22 convert the preload or
stored potential energy within the wires 20, 22 into biasing forces
which shift the sliders 18A, 18B in direction 24 and sliders 18C,
18D in direction 26. The shifting of the sliders 18 in directions
24, 26 urges the bones 84, 86 together and removes the gap 88
therebetween. In one embodiment, the wires 20, 24 are able to shift
the sliders 18 from the end portions 62 of the through openings 14
to the opposite end portions 64 of the through openings 14.
Further, depending on patient anatomy, the wires 20, 24 may urge
the sliders 18 less than the entire distance along the through
openings 14. If the sliders 18 are spaced from the laterally
extending walls of the bone plate 12 at the end portion 64 of the
through opening 14, the wires 20, 22 will be bent and will continue
to apply a biasing force to the sliders 18.
With reference to FIG. 6, the wires 20, 22 are shown in an unloaded
configuration after the spacers 36 have been removed and the wires
20, 22 have urged the sliders 18 to the end portions 64 of the
through openings 14. In the unloaded configuration, the wires 20,
22 are substantially straight with the end portions 104, 106 being
generally coaxial with the intermediate portion 107. However, in
other embodiments, the wires 20, 22 may still be bent in unloaded
configuration such as if the patient's anatomy prevents the sliders
18 from shifting the full distance across the through openings 14.
By comparing FIGS. 4 and 6, the end portions 104, 106 wiggle or
pivot from a transversely extending orientation relative to each
other to the coaxial orientation relative to each other as the
wires 20, 22 shift from the loaded configuration to the unloaded
configuration.
With reference to FIG. 7, the wires 20, 22 may be made of a
super-elastic material such as nitinol which has a stress-strain
graph 150. The nitinol wires 20, 22 have a first characteristic
(e.g. spring constant) when they are biasing the sliders 18 in
directions 24, 26 (see FIG. 2) toward the end portions 64 of the
through openings 14 such as after the spacers 36 are removed from
the bone plate 12. However, the nitinol wires 20, 22 have a second
characteristic (e.g. spring constant) that is different than the
first characteristic when the sliders 18 are shifted in directions
27, 29 toward the end portions 62 of the through openings 14 such
as if the bones 84, 86 are being urged apart due to patient
movement. With reference to FIG. 1, the different first and second
characteristics cause the wires 20, 22 to provide a greater
resistance force to movement of the sliders 18A, 18B in direction
29 and sliders 18C, 18D in direction 27 than the force the wires
20, 22 apply against the sliders 18 to shift the sliders 18A, 18B
in direction 24 and sliders 18C, 18D in direction 26. The higher
resistance to shifting of the sliders 18 in directions 27, 29
causes the wires 20, 22 to act as one-way slide control mechanisms
that effectively limit sliding movement of the sliders 18 to
directions 24, 26 while inhibiting sliding movement of the sliders
18 in directions 29, 27.
The different characteristics of the nitinol wires 20, 22 may be
due to the stress-induced formation of some martensite in the
superelastic nitinol of the wires 20, 22 above the normal
temperature of martensite formation. Because the martensite has
been formed above its normal formation temperature, the martensite
reverts immediately to undeformed austenite as stress is removed.
Austenite is higher strength than martensite and is stronger
against bending of the nitinol wires 20, 22 back toward their
loaded configuration.
For example, if the wires 20, 22 start at position A in graph 150
when bone plate system 10 is secured to the bones 84, 86, removing
the spacers 36 allows the wires 20, 22 to shift the sliders 18
toward the end portions 64 of the through openings 14. The moving
of the sliders 18 in the unloading direction releases stress in the
wires 20, 22 and causes the stress and strain of the wires 20, 22
to move toward position B. As the sliders 18 further compress the
bones 84, 86 together, the stress and strain of the wires 20, 22
moves to position C in stress-strain graph 150. However, if
post-surgical patient movement imparts loading in direction 27 on
the associated bone screw 30, the wires 20, 22 of the slider 18D
resist this movement and the stress and strain within the wires 20,
22 jumps to position D in the stress-strain graph 150. The jump to
the upper band of the stress-strain graph 150 indicates that the
stress in the material is much higher which translates into greater
resistance to bending of the wires 20, 22 back toward their loaded
configuration.
With reference to FIG. 8, the sliders 18 and wires 20, 22 of each
slider are shown prior to assembly with the bone plate 12. During
assembly, the sliders 18 are inserted in direction 160 into the
through openings 14. The sliders 18 are positioned in their
unloaded positions, i.e., at the end portions 64 of the through
openings 14.
Next, the wires 20, 22 are provided in a straight, unloaded
configuration. The end portions 104 of the wires 20, 22 are
advanced in direction 162 through apertures 116 of the bone plate
12, through the passageways 23, 25 of the sliders 18, and into the
through apertures 114 of the opposite side of the bone plate 12.
The wires 20, 22 are thereby positioned so that the intermediate
portion 107 of each wire 20, 22 extends through the respective
passageway 23, 25, the end portion 104 of each wire 20 is received
in one of the through apertures 114, and the end portion 106 of
each wire 20, 22 is received in one of the through apertures
116.
The sliders 18 are then shifted in preloading directions 164, 166
toward the loaded positions thereof, i.e., toward end portions 62
(see FIG. 2) of the through openings 14. Shifting of the sliders 18
in the preloading directions 164, 166 loads or bends the wires 20,
22 and creates gaps 64A (see FIG. 2) between the sliders 18 and the
laterally extending walls 52, 53 of the bone plate 12. The shifting
of the sliders 18 in preloading directions 164, 166 may be
performed by a technician utilizing a tool or an automated machine
as some examples.
With reference to FIG. 8, to connect the spacers 36 to the bone
plate 12, the spacers 36 are generally advanced in a direction 160
into the gaps 64A between the sliders 18 and the nearby bone plate
laterally extending walls 52, 53 while the sliders 18 are held in
the loaded position thereof by the technician or automated machine.
Once the spacers 36 are positioned in the gaps 64A, the sliders 18
are released and the wires 20, 22 of each slider 18 urge the
sliders 18 against the spacers 36 which clamps the spacers 36
between the sliders 18 and the laterally extending bone plate walls
52, 53. The process of shifting the sliders 18 to the loaded
position and connecting the spacers 36 to the bone plate 12 may be
performed on all of the sliders 18 at once, or may be performed on
fewer than all of the sliders 18 (e.g., one or more) at a time.
Regarding FIG. 9A, the bone plate 12 includes an end wall 170
opposite the laterally extending wall 52 and side walls 172, 174
through which the apertures 114, 116 extend. The apertures 114, 116
have a varying profile throughout to accommodate the movement of
the end portions 104, 106 of the wires 20, 22. Further, each
through opening 14 has a longitudinal axis 175 extending between
the end portions 62, 64 of the through opening 14. Although the
following discussion refers to through aperture 114, it will be
appreciated that the through aperture 116 is a mirror image of the
through aperture 114 such that the following discussion also
applies to through aperture 116, wire end portion 106, and side
wall 174.
The through aperture 114 includes a narrow portion 180 having a
distance 182 thereacross and an enlarged portion 184 having a
distance 186 thereacross that is larger than the distance 182. The
enlarged portion 184 provides clearance for the end portion 104 of
the wire 20 to move from the oblique or transverse orientation
thereof when the wires 20, 22 are in the loaded configuration (see
FIG. 4) to the parallel or coaxial orientation when the wires 20,
22 are in the unloaded configuration thereof (see FIG. 6).
The side wall 172 also includes features that support the end
portion 104 of the wires 20, 22 while minimizing stress imparted to
the wires 20, 22. For example, the side wall 172 includes an angled
surface 190 that extends at an acute angle 192 relative to an axis
120 extending laterally through the apertures 114, 116.
With reference to FIGS. 9B and 11, the sliders 18 have a generally
rectangular configuration and through openings 14 have a generally
rectangular configuration that is longer than the sliders 18 to
permit the sliders 18 and bone screws 30 therein to slide
longitudinally within the through opening 14 along the bone plate
12. The slider 18 includes a body 220 having lateral sides 222,
224. The sides 222, 224 include flat surfaces 226, 227 for facing
flat surfaces 208, 210 of the bone plate side walls 172, 174 as
shown in FIG. 9B. The passageways 23, 25 of the slider 18 includes
openings 230, 232 that open to the sides 222, 226 (see FIG. 14).
The facing flat surfaces 208, 226 and 210, 227 of the sliders 18
and the bone plate 12 resist turning of the sliders 18 within the
through openings 14.
Regarding FIG. 10, the side walls 172, 174 of the bone plate 12
include wall portions 200, 202 above and below the wires 20, 22
when the wires extend through the apertures 114, 116. The wires 20,
22 support the sliders 18 within the through openings 14 of the
bone plate 12 against movement of the sliders 18 in directions 204,
205 out of the plane of the bone plate 12. The wires 20, 22 are
made of a material and have an adequate diameter to be sufficiently
strong in shear to resist the loading applied to the sliders 18 by
the bone screws 30.
With reference to FIG. 12, the lateral sides 222, 224 of the slider
18 extend longitudinally between front and rear sides 240, 242.
Further, the passageways 23, 25 extend through the slider 18 and
include an angled surface 298 and a rounded surface 316 that lead
into the passageways 23, 25 from the sides 222, 224.
Turning to FIG. 13, the passageway 25 includes enlarged side
portions 254, 256 for receiving the wire 22 and permitting the end
portions 104, 106 space to pivot or wiggle as the wire 22
straightens toward the undeflected configuration thereof. With
reference to FIG. 14, the passageway 23 of the slider 18 varies in
size as the passageway 23 extends laterally across the slider 18 to
provide support to the wire 20 when wire 20 is in deflected
configuration thereof and provide clearance for the wire 20 as the
wire 20 moves from the deflected configuration to the undeflected
configuration. The passageway 23 includes enlarged side portions
232, 230 and an intermediate portion 270. The passageway 23 has a
first distance 272 thereacross at the enlarged side portion 232, a
second distance 274 thereacross intermediate the enlarged portion
232 and the intermediate portion 270, and a third distance 276 at
the intermediate portion 270. The distance 272 is greater than the
distance 274 which is in turn greater than the distance 276.
Similar sizing exists at the enlarged side portions 230.
The slider 18 includes a wall 280 that abuts against or is a close
proximity to a laterally extending wall of the bone plate 12 such
as walls 52, 170 when the slider 18 is in the loaded position
thereof. The slider 18 also includes the wall 100 extending around
the through bore 32. The wall 280 may extend generally straight
laterally across the slider while the wall 100 includes an angled
surface 290, a rounded corner 292, an intermediate support surface
294, a rounded corner 296 and an angled surface 298 at the
passageway 23. The angled surfaces 290, 298 each extend an angle
300 relative to the lateral axis 302 that extends straight through
the passageway 23.
Similarly, the passageway 25 includes the enlarged side portions
254, 256 and a wall 102 extending generally laterally across the
slider 18. The slider 18 also includes the wall 102 having a
rounded surface 312, an intermediate support surface 314, and a
rounded surface 316. The passageway 35 varies in size as the
passageway 25 extends through the slider 18 including having a
dimension 317 at the enlarged side portion 254 and a smaller
distance 318 thereacross at an intermediate portion 320 of the
passageway 25.
FIG. 15 shows the wires 20, 22 in the deflected or loaded
configuration thereof wherein the end portions 104, 106 of the
wires 20, 22 extend outward from the lateral sides 222, 224 of the
slider 18 for connecting to the bone plate 12. In the loaded
configuration, the wires 20, 22 include outer intermediate portions
330, 332 that extend along and are supported by the angled surfaces
290, 298 and rounded surfaces 312, 316. The wires 20, 22 further
include the intermediate portions 107, 340 that are supported,
respectively, by the intermediate support surfaces 294, 314.
Further, the rounded corners 292, 296 and rounded surfaces 312, 316
provide support without sharp corners which reduces stress in the
wires 20, 22. Each wire 20, 22 generally has one bend 295 with a
shape complimentary to the either the surfaces 292, 294, 296 or the
surfaces 312, 314, 316. The walls 100, 102 of the slider 18 may
thereby be configured to compliment a desired amount of bend 295 of
the wires 20, 22 while limiting stress imparted to the wires 20, 22
supported by the walls 100, 102.
With the wires 20, 22 in the loaded configuration, the wires 20, 22
each extend at an angle 352 relative to the lateral axis 302 of the
passageways 23, 25. The angles 352 may be the same or different
depending on a particular application. With respect to the wire 20,
the outer intermediate portion 330 is separated by a distance 342
from the wall 280 by a gap 350 which increases in size as the wire
20 extends away from the intermediate support surface 294 as shown
in FIG. 15. The gap 350 provides clearance for the outer
intermediate portion 330 to move once the spacer 36 have been
removed from the bone plate 12 and the wire 20 can straighten out.
The wire 22 likewise has a gap from the wall 100 that varies as the
wire 22 extends laterally outward.
With respect to FIG. 16, the wires 20, 22 are shown in the
undeflected configuration such as after the spacer 36 has been
removed from the bone plate 12. The outer intermediate portions
330, 332 of the wires 20, 22 pivot in direction 360 into contact
with the wall 100, 280. This causes a gap 362 to separate the outer
intermediate portions 330, 332 of the wire 20 from the angled
surfaces 290, 298 of the wall 100 of the slider 18. The wire 20 is
spaced from the wall 100 by a distance 364 that increases as the
wire 20 extends laterally away from the intermediate support
surface 294. Likewise, the outer intermediate portions 330, 332 of
the wire 22 are spaced by a gap 368 from the curved surfaces 312,
316 of the wall 102.
Regarding FIGS. 2 and 17, each shoulder 70 of the spacer 36 defines
a notch 380 that receives a corner 382 of the bone plate 12 when
the spacer 36 is connected to the bone plate 12. The shoulder 70
has a lower surface 384 that rests on the upper surface 72 of the
bone plate 12. The head 40 has a tapered surface 386 that extends
downwardly from a circular upper surface 388 to a cylindrical,
radially outer surface 390 of the head 40. The surface 384 contacts
the upper surface 72 of the bone plate 12 and the slider 18 and
resist tilting or other movement of the spacer 36 which may lead to
unintentional removal of the spacer 36 from the bone plate 12, such
as during handling of the bone plate 12 prior to being placed at
the surgical site. Further, the flats 54, 56 of the spacer 36 are
normal to the biasing force and reactionary force imparted on the
spacer 36 by the slider 18 and the bone plate 12 which facilitates
secure clamping of the spacer 36 to the bone plate 12.
The tapered surface 386 is configured to cam resilient fingers 400
of the spacer removal instrument 50 (see FIG. 19) radially outward
as the instrument 40 is connected to the spacer 36 and the
resilient fingers 400 are advanced in direction 392 along the head
40. Once the resilient fingers 400 have advanced past the
cylindrical surface 390, the resilient fingers 400 snap below the
underside surface 74 of the head 40 of the spacer 36. With the
resilient fingers 400 below the underside surface 74 of the head
40, the user may pull upward on the instrument 50 in direction 396
and withdraw the body 42 from between the slider 18 and the bone
plate 12. The movement of the instrument 40 in direction 396
engages the resilient fingers 400 with the underside surface 74 of
the head 40 and draws the spacer 36 out from the gap 64A between
the slider 18 and the bone plate 12.
The body 42 of the spacer 36 includes a lower body portion 393
having a thickness 395 measured between the flats 54, 56. The
thickness 395, in combination with the geometry of the slider 18
and bone plate 12, is selected to hold the wires 20, 22 in the
loaded configuration with the maximum desired deformation in the
wires 20, 22.
With reference to FIG. 18, the bone screws 30 each include the head
portion 34 and a shank portion 404. The shank portion 404 includes
threads 406 for driving into bone. In one embodiment, the shank
portion 404 is configured to be self-tapping. The head portion 34
includes a rotary drive structure, such as a socket 406, that
receives a screwdriver such as a hexa-lobed screwdriver. The head
portion 34 further includes a curved lower surface 408 for engaging
a seating surface 410 (see FIG. 9B) of the slider 18.
With reference to FIG. 19, the spacer removal instrument 50
includes a handle assembly 420 and a shaft assembly 422. The shaft
assembly 422 includes a distal end portion 424 configured to engage
one of the heads 40 of the spacers 36 and a proximal end portion
425 connected to the handle assembly 420. The handle assembly 420
includes a stationary grip 428 and a handle 426 pivotally connected
to the stationary grip 428 by a pin 429.
With reference to FIG. 20, the shaft assembly 422 includes an outer
sleeve 430 mounted to the stationary grip 428 and an inner shaft
432 connected to the handle 426. The inner shaft 432 includes a rim
440 having the one or more resilient fingers 400 mounted thereto.
The resilient fingers 400 are mounted to the inner shaft 432 with
pins that extend through openings 441 (see FIG. 21A) of the
resilient fingers 411. In another embodiment, the inner shaft 432
and the one or more resilient fingers 400 have an integral
construction rather than being assembled. The inner shaft 432 also
includes a cannula 442 for holding the spacers 36 in a line within
the cannula 442 as the spacers 36 are removed one by one from the
bone plate 12. In another embodiment, the grip 428 may be movable
and the handle 426 may be fixed or both the grip 428 and the handle
426 may be movable to operate the instrument 50.
With reference to FIGS. 21A-21C, a method is provided for removing
a spacer 814 from a bone plate 802 of a bone plate system 800 (see
FIG. 31) using the instrument 50. First, a user holds the
instrument 50 so that the opening 446 of the inner shaft 432 is
adjacent a head 815 of the spacer 814. The user advances the
instrument 50 in direction 405 toward the bone plate 802 until the
head 815 enters the opening 446 and the resilient fingers 400 snap
below the head 815 of the spacer 814. The user then pivots the grip
426 in direction 450 (see FIG. 20) while pressing the instrument 50
against the bone plate 802. The pivoting of the grip 426 causes the
inner shaft 432 to shift in direction 447 relative to the outer
sleeve 430 and engages the resilient fingers 400 with the underside
of the head 815. As the inner shaft 432 shifts in direction 447, a
rim 449 of the outer sleeve 430 contacts the bone plate 802 and one
of the sliders 808 therein. As shown in FIGS. 21B and 21C, the
user's moving of the handle 426 toward the stationary grip 428
causes the inner shaft 432 to pull the spacer 814 in direction 447
outward from the bone plate 802.
Once the spacer 814 has been removed from the bone plate 802, the
user releases the handle 426 and the handle 426 may be biased back
toward its initial position by a spring of the instrument 50. With
reference to FIG. 21D, the user then positions the instrument 50 at
a second spacer 814. Although the first spacer 814 is held by the
resilient fingers 400 within the cannula 442, the user may simply
press the instrument 50 in direction 405 onto the second spacer 814
which causes the second spacer 814 to shift the first spacer 814
farther into the cannula 442 and beyond the resilient fingers 400
as shown in FIG. 21D. The instrument 50 is pressed in direction 405
until the resilient fingers 400 snap below the head 815 of the
second spacer. Next, the user pivots the handle 426 toward the
stationary grip 428 which causes the inner shaft 432 to shift in
direction 447, the outer sleeve to engage the bone plate 802/slider
808, and the inner shaft 432/resilient fingers 400 to pull the
second spacer 814 out of the bone plate 802 as shown in FIGS. 21D
and 21E.
With reference to FIG. 22, a bone plate system 600 is provided that
includes a bone plate 602 and slider assemblies 604 that receive
bone screws 606 and are shifted along throughbores 608 of the bone
plate 602 by biasing assemblies 610 once spacers 612 of the bone
plate system 600 have been removed. The slider assemblies 604
include sliders 604A, 604B and 604C. The slider assemblies 604A,
604B are identical to the slider assemblies 16 discussed above.
However, the slider assembly 604C is different and includes a
slider 614 having two throughbores 616 for receiving two bone
screws 606.
With reference to FIG. 23, the slider assembly 604C includes the
slider 614 and one or more resilient members, such as wires 620,
622. The wires 620, 622 each have end portions 624, 626 that extend
outward from sides 628, 630 of the slider 614 and engage through
apertures 632 of the bone plate 602.
With reference to FIGS. 24 and 25, due to the lateral extent of the
slider 614, the slider 614 has a curvature to compliment the
curvature of an outer surface of a bone while minimizing
interference with surrounding tissues. In the illustrated
embodiment, the slider 614 includes a concave lower surface 634 and
a convex upper surface 636. Due to the curvature of the slider 614,
the wires 620, 622 have a complex curvature throughout the slider
614. More specifically and with reference to FIG. 24, the slider
614 includes passageways 640, 642 and the wires 620, 622 extend
upwardly and to the left (as seen in FIG. 24) into the passageways
640, 642 at the side 628.
With reference to FIG. 26, the passageways 640, 642 each include an
outer enlarged portion 650 and a narrow intermediate portion 652.
The slider 614 includes a wall 654 extending around each
throughbore 616 and the wall 654 includes an angled surface 656,
curved corner 658, and an intermediate support surface 660. The
slider 614 includes a wall 662 opposite the wall 654 and across the
passageway 640. As discussed above with respect to the sliders 18,
the outer enlarged portion 650 of the passageway 640, 642 permits
movement of an outer intermediate portion 670 of the wires 620, 622
as the wires 620, 622 straighten from a loaded configuration to an
unloaded configuration and the outer intermediate portions 670
pivot in direction 674. The wires 620, 622 include intermediate
portions 680 that contain a bend 740 (see FIG. 29) out of the page
in FIG. 26 as well as inner intermediate portions 682 that are
connected to the outer intermediate portions 670 by bends 684
generally in the plane of the cross section taken of FIG. 26.
With reference to FIG. 27, the passageway 642 is shown and it will
appreciated that the passageway 640 is similar in many respects.
More specifically, the passageway 642 includes a first passageway
portion 712 extending inward from side 628 and having an axis 700.
The passageway 642 includes a second passageway portion 714
extending inward from the side 630 and having an axis 702 therein.
There is an angle 704 between the axes 700, 702. The angle 704
forms a bend 740 (see FIG. 29) in the intermediate portion 680 of
the wire 622 to provide enough material in a lower wall 706 of the
slider 614 and accommodate the concave lower surface 634. The
slider 614 includes an upper wall 708 having a through opening 710
therein that permits viewing of the wire 622. Through opening 710
may be formed during manufacture of the slider 614 by a machine
tool that enters the passageway 642 from above and machines out
material as needed. In other embodiments, the through opening 710
is not utilized such as if the slider 614 is produced using
additive manufacturing. The lower wall 706 includes an inclined
surface 716 in the first passage portion 712 to support one of the
inner intermediate portions 682 of the wire 622 and an inclined
surface 718 in the second passageway portion 714 to support the
other inner intermediate portion 682. Likewise, the upper wall 708
includes inclined surfaces 722, 724 which together with the lower
inclined surfaces 716, 718 maintain the bend 740 in the
intermediate portion 680 whether the wire 622 is in the loaded or
unloaded configuration thereof.
With reference to FIG. 28, the wire 622 is shown removed from the
slider 614 and is in the loaded configuration thereof. In the
loaded configuration, the outer intermediate portion 670 is at an
angle 730 relative to the inner intermediate portion 682 and forms
two bends 684 in the wire 622. Whereas FIG. 28 is a top plan view,
FIG. 29 is a rear elevation view of the wire 622 in the loaded
configuration thereof. As discussed above with respect to FIG. 27,
the first passageway portion 712 and the second passageway portion
714 create the bend 740 in the intermediate portion 680 of the wire
622 to provide clearance for the concave lower surface 634 of the
slider 714. The bend 740 positions the outer intermediate portions
670 at an angle 742 relative to one another. Thus, when the wires
620, 622 are in the loaded configuration, each wire 620, 622 has
three bends including the two bends 684 and the bend 740. Once the
spacer 612 has been removed from the bone plate 602 and the pins
620, 622 urge the slider 614 to an unloaded position thereof, the
bends 684 straighten out in a manner similar to the straightening
of the bend 295 as one goes from FIG. 15 to FIG. 16. However, even
once the slider 614 has shifted to the unloaded position, the
passageways 640, 642 maintain the bend 740 in the intermediate
portions 680 of the wires 620, 622 because the inner intermediate
portions 682 are constrained against movement unlike the outer
intermediate portions 670.
With reference to FIG. 30, the wire 622 is shown in a side
elevational view to illustrate how each of the bends 684 orients
the outer intermediate portion 670 thereof to extend transversely
to the inner intermediate portions 682. Further, the bend 740
provides the vertical component (as shown in FIG. 30) of the extent
of both the outer intermediate portion 670 and the inner
intermediate portion 672 of the wire 622. When the spacers 612 are
removed from the bone plate 602, the outer intermediate portions
670 pivot in direction 674.
With reference to FIG. 31, the bone plate system 800 is similar in
many respects to the bone plate system 10 discussed above. The bone
plate system 800 includes a bone plate 802 having through openings
804 that receive slider assemblies 806. The slider assemblies 806
include sliders 808 having throughbores 810 that receive bone
screws 812. The bone plate system 800 includes spacers 814 that may
be removed from the bone plate 802 to permit the slider assemblies
806 to shift to unloaded positions which compresses bones connected
to the bone screws 812. One difference between the bone plate
system 800 and the bone plate system 10 discussed above is that the
bone plate 802 has a dog bone-shaped configuration with enlarged
end portions 816, 818 and a narrowed intermediate portion 820. The
narrowed intermediate portion 820 forms notches 822, 824 on
opposite sides of the bone plate 802. Each end portion 816, 818
includes two throughbores 810 to receive two slider assemblies
806.
Regarding FIGS. 32-35, a bone plate 900 is provided that is similar
in many respects to the bone plate 12 discussed above. The bone
plate 900 may be utilized in the bone plate system 10 instead of
the bone plate 12. For example, the bone plate 900 includes through
openings 902 configured to receive the slider assemblies 16. The
bone plate 900 includes side walls 903 with apertures 904 for
receiving end portions of the wires 20, 22 of the slider assemblies
16. Regarding FIGS. 34 and 35, each aperture 904 includes an angled
surface 906 for supporting the associated wire 20, 22 and providing
a more gradual bend of the wire 20, 22 when the sliders 18 are held
in the loaded configuration in the through openings 902 by the
spacers 36. Regarding FIG. 33, the bone plate 12 has a varying
thickness between upper and lower surfaces thereof including a
thinner intermediate portion 910 between thicker side portions 912.
The thinner intermediate portion 910 may include, for example, a
generally concave surface portion. Conversely, the lower surface
914 of the bone plate 900 may have a generally concave surface
portion. The thinner intermediate portion 910 provides a reduced
thickness along the midline of the plate which may improve
interaction with surrounding tissues for some patients.
While there have been illustrated and described particular
embodiments of the present invention, it will be appreciated that
numerous changes and modifications will occur to those skilled in
the art, and it is intended for the present invention to cover all
those changes and modifications which fall within the scope of the
appended claims.
* * * * *
References